In the electro-luminescence device according to the present invention, the electro-luminescence is generated by applying an alternating electric field to two electrodes in which a luminous material which is activated by an electric field is sandwiched therebetween.
For an electro-luminescence device using a transparent substrate such as a glass plate on the luminous surface side, a means of applying a moisture impermeable plate such as a glass plate to the back side thereof as a back protective material and sealing the periphery with a resin is proposed in JU-A-59-129197 (the term "JU-A" as used herein means an "unexamined published Japanese utility model application"), as shown in FIG. 4 of the accompanying drawings. That is, as shown in FIG. 4, the electro-luminescence device disclosed in JU-A-59-129197 is composed of a laminate of glass substrate 10, transparent electric conductive film 11, fluorescent layer 18, dielectric layer 17, back electrode 16, and glass substrate 14. In the device, the periphery is sealed with sealing resin 20. In addition, element 12 is a current collector, elements 13 and 19 are leading wires, and element 15 is a laminate (composed of 16, 17, 18 and 19). However, the foregoing means takes time for sealing the periphery of the electro-luminescence device with the resin and hence is not a good, efficient method for industrial use.
For improving the above-described problem, JP-A-62-76279 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") proposes a method wherein, as shown in FIG. 3 of the accompanying drawings, electro-luminescence element 4, which is composed of a laminate of a polyester film and an electro-luminescence layer, is placed between transparent substrate 1 and back protective material 3 through adhesive resin films 2 and 2', respectively, and after heating, they are integrated in a body under a reduced pressure. As the adhesive resin film used in the foregoing method, a film of a thermoplastic resin such as an ethylene-vinyl acetate copolymer, a polyvinyl butyral, etc., having a thickness of about 800 .mu.m is used. This is a well known sealing method in this art.
In the method of JP-A-62-76279, the efficiency of the adhesive property is improved but, as will be understood from FIG. 3, since the thickness of adhesive resin film 2 disposed between transparent substrate 1 and luminous layer 4 becomes uneven during the steps of softening by heating and caking by cooling in the adhesive step, a wavy pattern is observed on the surface of the finished electro-luminescence device, which reduces the beautiful appearance of the finished product.
Also, JP-A-62-188197 discloses an electro-luminescence device wherein, as shown in FIG. 2 of the accompanying drawings (also showing a process for manufacturing the electro-luminescence device of the present invention), transparent electrode 2, luminous layer 3, dielectric layer 4, and back electrode 5 are successively laminated on transparent substrate (glass substrate) 1 and an aluminum composite sheet is adhered to the back electrode side through adhesive resin intermediate film 7 as back protective material 6. The aluminum composite sheet used in the above electro-luminescence device is composed of an aluminum foil, both surfaces of which are laminated with a resin film. Since the foregoing electro-luminescence device does not have a resin film between transparent substrate 1 and luminous layer 3 and thus is different from the structure shown in FIG. 3 described above, the problem of reducing the appearance by the unevenness of the thickness of the adhesive resin film is solved. However, since in the electro-luminescence device, the end portions of adhesive resin intermediate film 7 are exposed at the edge portions of the electro-luminescence device, moisture permeates into the electro-luminescence device from the ends thereof, whereby a sufficient moisture resistance for practical use is not obtained.
JP-A-2-214129 proposes that for preventing the permeation of moisture from the ends of the adhesive resin film, the width of the sealing end portions is increased as large as possible. Since the width of the sealing end portions is too large, though, a problem in the effective areas of the electric members occurs, and a problem of permeation of moisture from the protective film occurs. Accordingly, an equation for calculating a preferred width of the sealing end portions from the thickness and moisture permeability of the protective film and the thickness and moisture permeability of the adhesive resin film is proposed. However, in the foregoing technique, there is a limit in the moisture permeability of the product, since the protective resin film has a moisture permeability to some extent.